Explanation:

Let Ram’s , Shyam’s and Balram ‘s present age is x, y and z years respectively .

We have x = y + 4 , y = 2z and z = 8 years

Thus y = 2×8 = 16 years

And x= y + 4 = 16+4=20 years

Therefore , Ram ‘s age at the time of birth of Balram = 20 – 8 = 12 years